Voltage regulator adjustment



J. A. UMBARGER in AL VOLTAGEREGULATOR ADJUSTMENT Filed Sept. 8, 1949Nov. 11, 1952 INVENTORS:

JAMES A-UMBARGER GLEN E. HEVERAN ATT'Y Patented Nov. 11, 1952 VOLTAGEREGULATOR ADJUSTIVIENT James Andrew Umbarger and Glenn E. Heveran,

Waukegan, IiL, assignors, by mesne assignments, to ReconstructionFinance Corporation, Chicago, 111., a corporation of the United StatesApplication September 8, 1949, Serial No. 114,621

2 Claims.

This invention relates in general to a regulator for controlling anelectrical device through an enclosing casing. It is more particularlydescribed as a regulator for controlling the output of an automotivegenerator.

The ordinary type of controller for an automobile current generator forproducing current for recharging the battery comprises a cut out, acurrent limiter and a voltage regulator, all closely assembled, usuallyin a more or less convenient place and having a removable cover forencasing and enclosing them against tampering and ordinary manipulation.The most common method of adjusting the regulators heretofore has beento remove the protecting cover and by means of bending tools to alterthe tension or position of a spring of the voltage regulator or thecurrent limiter. The act of doing this properly is far more diflicultthan it sounds for the reason that it is impossible to tell whether thealtered tension of the spring is suflicient or too much. This difficultyis also increased by the fact that the act of replacing the coverusually alters the adjustment made, frequently necessitating severaltries before the desired result is obtained. This work frequently mustbe done by unskilled mechanics and under adverse conditions.

The present invention results from the realization of the need for asimple non-critical means of alterin the current or voltage setting ofthe regulator without removing the protective cover- An important objectof the invention is therefore in the provision of adjusting meansattachable to the cover of a regulator and extending through the coverto engage and move an adjustable member within the cover for varying theresistance of a spring or other variable adjusting means.

A further object of the invention is to provide an insulated meansextending through a cover for engaging an electrical device within thecover without altering the electrical resistance of any circuits orelectrical devices within the cover.

A further object of the invention is to provide an adjusting meansextending through a cover adapted to be fixed in position, the adjustingmeans having a fixed and lockable device engaged by a removable tool sothat adjustment is not readily made by unauthorized persons nor is theadjustment likely to become changed or altered except by the applicationof a proper tool.

Other objects of the invention will appear in the specification and willbe apparent from the accompanying drawings in which,

Fig. 1 is a perspective view of the outside of a voltage regulator foran automotive generator which includes an enclosing cover with theadjusting means of the present invention as applied thereto andaccessible from the outside;

Fig. 2 is a sectional view showing the cover and the present inventionin section and portions of the operating parts of the voltage regulatoras enclosed by the casin in elevation, the variable member of thisinvention engaging the spring contact of the voltage regulator for anautomobile generator; and

Fig. 3 is a diagrammatic representation of a regulator to which thepresent invention is applied for connection to an automotive generator,a storage battery supplied thereby and a current load from the storagebattery.

While this invention is particularly described as applied to a voltageregulator for an automobile generator, it may also be utilized inconnection with any casing which is preferably fixed to encloseelectrical operating parts, but requires adjustment of the parts withinthe cover. It is particularly applicable to the current regulation of anautomotive generator because it is frequently desirable to change theamount of current which is supplied to the storage battery depending forexample upon summer or winter driving, and depending somewhat upon theamount of day and night driving of any particular automobile.

Referring now more particularly to the drawings, the electric regulatorcomprises generally a cut out, a current limiter and a voltage regulatorenclosed by a cover l0 applied to a supporting base 12 by fixedfastening means M at the ends thereof. In the top of the cover is anopening it which is covered by a thin plate 18 and firmly fastened tothe cover by fastening rivets 20 at the corners thereof. At the insideof the plate and projecting inwardly through the openin l6 within thecover is a flat spring 22 secured by rivets 24 at one end to the plateI8 offset downwardly from the plate intermediate its ends and having aninsulating contact member 26 secured at the other end and projectingoutwardly therefrom.

To adjust the position of the spring 22 and the engagement of thecontact 26, a set screw 28 has a rounded or blunt extremity 30 to engagethe upper side of the spring 22 and preferably extends through a locknut 32 rigidly secured to the plate l8. At the top of the screw is arecessed angular opening 34 adapted to be engaged by a correspondingangular tool 36. The top of the screw is preferably flush with the fixednut 32 so that the adjusting screw is not easily turned except by aparticular tool therefor and the adjusting screw is held firmly in placein any adjusted position.

The voltage regulator within the casing has a fiat spring S (see Fig. 3)fixed at one end and normally closing contacts C at the other end. Thisspring is opposed by an electro-magnet having an armature VR and awinding coil ER which when energized tends to withdraw the spring S andseparate the contacts C. The regulation of this electro-magnet is suchthat as the regulator is depressed from the cover to engage the springS, the voltage applied to the battery will be re-- duced and as thepressure of the regulator is reduced by less tension on the spring 22,the voltage applied to the battery will be increased as hereinafter setforth.

The current limiter is represented as having an armature CL with amagnet winding IL for controlling a spring SL which maintains contactsCL normally closed.

The cut out is represented as an electro-responsive device having anarmature CO with differential windings EC and 10, the latter attached toone end of a spring S for controlling contacts LO normally open andclosed when the winding EC is energized but opened by the winding ICunder certain conditions.

The terminals of this regulator are designated as A for the armature, Ffor the field and B for the battery. A generator G is represented ashaving an armature connected to ground, a generator field GF connectedby a conductor G9 to the terminal F and the other end of the fieldconnected by conductor 2 to the armature terminal A.

A storage battery SB is connected by a conductor M to the regulatorterminal B with conductors 36 extending from the battery for the carlights, radio, and the like, and the other side of the battery connectedby a conductor 48 to a ground which may be the frame of a car to whichthe invention is applied. The other terminal of the cut out winding isconnected by a conductor 50 to the regulator terminal A. One terminal ofthe cut out winding EC is connected by a conductor 52 to the armatureterminal A, the other terminal being connected to ground. One terminalof the winding ER of the voltage regulator is connected by a conductor54, to armature terminal A, the other terminal of the winding beingconnected to ground. One terminal of the current limiter winding IL isconnected by conductor 56 with a contact LO of the cut out switch S0 andthe other terminal of this'winding is connected by a conductor 58 to the:battery terminal B. p

The current limiter switch SL is connected by a conductor 60 with thefield terminal F and one of the contacts CL of the current limiterswitch is connected by a conductor 62 with the end of the voltageregulator switch S, one of the terminals C of the switch S beingconnected by a conductor 64 to ground. The field terminal is alsoconnected by a conductor 65 through a resister 68 to ground.

With this construction, the voltage coil EC of the cut out produces amagnetic pull against the spring SO causing the contacts L0 to closewhen and if the voltage from the generator becomes sufiiciently great.With these contacts closed, current can flow from the generator armaturethrough the current coil 10 of the cut out, the cut out contacts L0 andthe current limiter coil IL through conductor 58 to the storage battery.

With the battery now connected across the generator, the cut outcontacts will be electrically locked in closed position by the batteryvoltage regardless of the electro-motive force of the generator. Exceptfor the effect of the coil IC, a reverse current of destructivemagnitude would flow from the battery to the generator during the timeswhen the generator electro-motive force became much less than thebattery voltage which would be the case during very low speed operation;Under such conditions, however, the reverse current through the coil 10'opposes the forces caused by the coil EC so that the resultant forcewill reach zero and release the cut out contacts before the reversecurrent exceeds a safe magnitude.

This invention does not relates to the out out. The invention doespertain to the current limiter and/or to the voltage regulator althoughit is shown as applied to the voltage regulator only. In order forcurrent to flow through the generator field winding to the ground, itmust pass from the regulator terminal F through the resistor 68 orthrough the contacts CL of the current limiter and the contact C of theVoltage regulator. With the contacts CL of the current limiter, and thecontacts C of thevoltage regulator both closed, nearly all of the fieldcurrent will flow through these contacts and through conductors 59, E2and 54 to ground. When either of these contacts open, the field currentWillfiOW only throughthe resistor andwill be reduced from its formervalue. This will cause the generator electro-motive force to be reducedand therefore its output voltage and current will be reduced. 7

When the current output of the generator through the current limitercoil IL becomes large enough to exert sufiicient force on the spring SLto open the contacts CL, the field current will be reduced as explainedabove until the force exerted rent limiter exerts no influence on thegenerator 7 under all other conditions which are attended by lessercurrents.

Similarly, the output voltage of the generator across the coil ER of thevoltage regulator causes a force to work against the spring S openingthe contact C, reducing the field current and the generator outputvoltage until a vibrating and regulating action results, as explainedfor the current limiter. An important fact is that with both the currentlimiter and the voltage'regulator, the value of the current or voltageat which the regulation takes place is dependent upon the zesiraiiningforce on the spring S and the conac Y 7 In the operation of thisinvention, the ad- 1 justment of the screw 28 changes the tension on thespring 22 and by reducing the effective pressure on the spring, it willmore asily respond to the forces caused by the winding coil ER, therebypermitting the regulating action to occur at a lower voltage. V

Backing the screw 28 out, produces the opposlte effect. Obvious theadture would alter its tension for compensating purposes; the springmight be fastened to the regulator strip instead of to the cover. In thelatter case, the only part needed in the cover is the contacting screw28.

Various other constructions may also be adopted for accomplishing thedesired result, but the present construction is particularly adapted forus because it may be incorporated with existing voltage regulatorswithout changing any part :of the electrical mechanism of the regulatoritself so that the present invention may be considered independent ofthe actual construction of the regulator mechanism itself so long as itincludes a spring element for closing contacts in the current limiter orvoltage regulator, the resistance of which is varied by an adjustingmeans extending through the cover of the regulator. The presentinvention is therefore independent of the specific electrical regulatorconstruction shown and may be applied to various types of regulameans tovary the spring for different voltages, a.

a cover for completely enclosing the voltage regulating parts, means forattaching the cover in fixed position with respect to the voltageregulator parts, an opening in the top of the cover adjacent the saidspring, a plate attachable over the opening to which one end of thespring is connected, the plate having a mounting device extendingtherethrough, an adjusting element threaded in the mounting device, theinner end of the adjusting element engageable with the sprinintermediate its ends to vary the pressure of the free end thereof andthus to vary the voltage at which it will be attracted for movement bythe electro-responsive device, and the outer end of the adjustingelement extending to the outside of the plate and to the outside of themounting device where the element is provided with an angular openingfor receiving a tool for rotating the element into and out of engagementwith the spring without removing the cover.

2. In combination, a voltage regulator for an electric generator,comprising at least one electro-responsive device which includes amovable contact and a flat spring pivoted at one end and actuated by anelectro-magnet for moving the contact at its other end, a cover forenclosing the voltage regulator and the electro-responsive device, thecover having an opening therethrough opposite the said contact movingspring, a plate and means to secure it in closed position over theopemng of the cover, a flat spring secured at one end to the under sideof the plate and offset inwardly therefrom, a contact maker at the otherend of the last spring to engage the first said spring which holds themovable contact, an ad- Justmg device comprising an element extendingthrough the plate with the inner end in engagement with the springattached to the plate intermediate the ends of the spring, a mountingdevice fixed in the plate and extending therethrough 1n which theadjusting device is threaded for ad usting movement, the outer end ofthe adustmg device being substantially flush with outside of themounting means and having an angular recess therein for engagement by atool to adust the pressure upon the spring attached to the plate fromthe outside of the cover without removing and thereby to vary thepressure upon the contact spring of the voltage regulator.

JAMES ANDREW UMLBARGER. GLENN E. HEVERAN.

REFERENCES CITED The following references are of record file of thispatent: m the UNITED STATES PATENTS Number Name Date 300,253 HazazerJune 10, 1884 1,576,768 Loudon Mar. 16, 1926 1,724,197 Hartzell Aug. 131929 2,238,383 Collins Apr. 15 1941 2,339,526 Thompson Jan. 18, 19442,358,482 Thompson Sept. 19, 1944 2,428,218 Herbst Sept. 30, 1947

